Slot 2 solution

I already have a solt 1 solution, the M3 Simply, but now I want a slot 2 solution. Many of the slot 2 solutions have an extra item for slot 1 called a "super key" or "pass card." Do I need a "super key" or "pass card" If I just want to use the Slot 2 solution for GBA backups? I figured I could use my M3 Simply for DS backups and then something like the SuperCard LITE for my GBA games.

So I guess what I'm asking is will the SuperCard LITE work on it's own for GBA games or would I still need one of the slot 1 devices even though DS backups won't be played?